Objective:

To determine the prevalence of and identify risk factors for clinical insomnia (CI) in patients with multiple sclerosis (PwMS).

Background:

PwMS are more likely to experience sleep disturbances, such as CI, than the general population. These disturbances may exacerbate MS symptoms and vice versa. Thus, it is important to identify risk factors for CI in PwMS while controlling for common MS treatment and disability metrics.

Design/Methods:

We administered the Insomnia Severity Index (ISI) survey to PwMS to determine their level of CI, if any. Then, we collected patient demographics and MS metrics such as expanded disability status score (EDSS). Finally, we used multivariate logistic regression to examine the relationships between CI (defined as an ISI score greater than or equal to 15) and pertinent covariates.

Results:

We included 92 PwMS in this study; 25% met the criteria for CI. Active treatment for depression (OR, 10.98; 95% CI 1.36-88.82; p=0.025) and higher annualized relapse rate (ARR) (OR, 19.04; 95% CI 2.06-176.19; p=0.009) both significantly increase risk of CI, while history of obstructive sleep apnea (OR, 0.10; 95% CI 0.01 -0.92; p=0.042) and non-Hispanic white race (OR, 0.13; 95% CI 0.02-0.85; p=0.034) both significantly decrease risk, controlling for EDSS, medication possession ratio, MS duration (years), and anxiety as determined by the Hospital Anxiety and Depression Scale. Of note, a majority of OSA positive patients were treated for OSA (54%; p<0.001).

Conclusions:

Our model suggests that active treatment for depression and higher ARR significantly increase the risk of experiencing CI in PwMS. Conversely, treated OSA and non-Hispanic white race were associated with a reduced risk. These results highlight key demographic and clinical factors that may help identify PwMS at higher risk CI, enabling earlier screening and treatment for sleep disturbances.